The objective of this project is to seek detailed knowledge about immune responses to antigens associated with rat colon cancer, and on one hand to develop methods to stimulate those responses that lead to tumor rejection establishing immunotherapeutic and prophylactic procedures and on the other hand to investigate the feasibility of using sequential assays of humoral antitumor antibodies for diagnostic purposes. Special emphasis will be put on lymphocyte separation with two-phase CCD technique, use of protein A-Sepharose or Staph. aur. Cowan I for immunoabsorption and lymphocyte stimulation. It will be studied whether tumor associated antigens contained in liposome vesicles may be used for lymphocyte stimulation and as targets in assays for humoral and/or cellular immunity.